Typical soft agar assays consist of a gel matrix of either methylcellulose, agarose, agar or plasma clot mixed with basal medium, fetal bovine serum and, if necessary, growth factors. The preparation of this semi-solid matrix culture system is both laborious and time-consuming. Another disadvantage of these culture systems is that the cells to be cultured must be added to the gel when the gel is in a liquid form for proper growth of the cells. The addition of cells to either the methylcellulose or SeaPlaque.RTM. alone, after it has formed a gel, does not support proliferation of the cells to form discrete colonies that can be quantitated to the extent necessary to run various biological tests, especially the soft agar assays.